首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   33921篇
  免费   3055篇
  国内免费   2508篇
耳鼻咽喉   239篇
儿科学   268篇
妇产科学   346篇
基础医学   3882篇
口腔科学   494篇
临床医学   4956篇
内科学   4868篇
皮肤病学   256篇
神经病学   1756篇
特种医学   1154篇
外国民族医学   21篇
外科学   3008篇
综合类   6060篇
现状与发展   5篇
一般理论   2篇
预防医学   2070篇
眼科学   1226篇
药学   3749篇
  27篇
中国医学   2117篇
肿瘤学   2980篇
  2024年   114篇
  2023年   571篇
  2022年   1493篇
  2021年   1789篇
  2020年   1365篇
  2019年   1231篇
  2018年   1138篇
  2017年   1191篇
  2016年   1013篇
  2015年   1632篇
  2014年   1925篇
  2013年   1621篇
  2012年   2521篇
  2011年   2814篇
  2010年   1724篇
  2009年   1376篇
  2008年   1824篇
  2007年   1782篇
  2006年   1824篇
  2005年   1999篇
  2004年   1080篇
  2003年   895篇
  2002年   804篇
  2001年   709篇
  2000年   679篇
  1999年   762篇
  1998年   536篇
  1997年   500篇
  1996年   390篇
  1995年   369篇
  1994年   303篇
  1993年   214篇
  1992年   231篇
  1991年   212篇
  1990年   191篇
  1989年   143篇
  1988年   146篇
  1987年   106篇
  1986年   101篇
  1985年   66篇
  1984年   29篇
  1983年   24篇
  1982年   11篇
  1981年   19篇
  1980年   9篇
  1979年   8篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
The present study was designed to detect three single nucleotide polymorphisms (SNPs) located on 22q11 that was thought as being of particularly importance for genetic research into schizophrenia. We recruited a total of 176 Chinese family trios of Han descent, consisting of mothers, fathers and affected offspring with schizophrenia for the genetic analysis. The transmission disequilibrium test (TDT) showed that of three SNPs, rs10314 in the 3'-untranslated region of the CLDN5 locus was associated with schizophrenia (chi(2) = 4.75, P = 0.029). The other two SNPs, rs1548359 present in the CDC45L locus centromeric of rs10314 and rs739371 in the 5'-flanking region of the CLDN5 locus, did not show such an association. The global chi-square (chi(2)) test showed that the 3-SNP haplotype system was not associated with schizophrenia although the 1-df test for individual haplotypes showed that the rs1548359(C)-rs10314(G)-rs739371(C) haplotype was excessively non-transmitted (chi(2) = 5.32, P = 0.02). Because the claudin proteins are a major component for barrier-forming tight junctions that could play a crucial role in response to changing natural, physiological and pathological conditions, the CLDN5 association with schizophrenia may be an important clue leading to look into a meeting point of genetic and environmental factors.  相似文献   
12.
In order to investigate the antagonistic effect of Glycyrrhiza Uralensis Fish (GUF) and Chelidonium maJus L (CML) on gastrccarcinogenesis induced by MNNG in Wastar rats, we treated the rats with MNNG alone (group 1) and with MNNG plus GUF and CML (group 2 and 3) respectively. The incidence of infiltrating adenocarcinoma of the glandular stomach and duodenum in group 2 was significantly lower than that in group 1 (26.7% vs. 67.8%). The differentiation and aggressivenees of carcinomas occured in group 2 were much better and mild than those in group 1. Present study also demonstrated that the inhibitory effect of CML on proliferation of human stomach carcinoma cell line MGC-803 was very remarkable; in addition, GUF and CML were able to antagonise the mutagenic activation of MNNG. These results suggest that GUF and CML may be empoyed in prevention of gastric carcinoma.  相似文献   
13.
永瓣藤化学成分的研究   总被引:2,自引:1,他引:1  
永瓣藤化学成分的研究陈玲,谢平,戚薇,曾菊珍(药学系中药化学教研室)关键词永瓣藤,化学成分,三萜,蒜盘子甾酮永瓣藤(MonimopetalnmChinenseRe-hd)系卫矛科永瓣藤属植物[1],为我国特有的珍稀二类保护植物[2],分布于江西东北部...  相似文献   
14.
目的 :探讨地塞米松减轻曲马多术后镇痛时恶心呕吐的临床效果。方法 :选择术后自愿硬膜外镇痛(PCEA)的病例 6 0例 ,随机分为试验组 (地塞米松 曲马多 0 .15 %布比卡因 )和对照组 (格拉司琼 曲马多 0 .15 %布比卡因 )。结果 :两组病人术后疼痛评分 (VAS法 ) ,镇静评分及恶心呕吐的发生率无明显差异 (P >0 .0 5 )。结论 :地塞米松可以减轻曲马多术后镇痛时恶心呕吐的发生 ,效果良好 ,不增加副作用 ,价格便宜  相似文献   
15.
本研究用酶联免疫吸附术观察8只家兔在附睾注射鱼肝油酸钠后血清及精浆中的抗精子抗体。血清抗精子抗体阳性率为37.5~50.0%,最早检出率为术后2个月,6~7月达高峰。精浆抗精子抗体阳性率为25%,最早检出率为术后4个月,且此时己达高峰。与输精管结扎资料相比,发现血清抗精子抗体检出率偏低,而精浆相应抗体偏高,表明向附睾注射鱼肝油酸钠引起的免疫反应有别于结扎,以生殖道局部为主。  相似文献   
16.
Q Chen  P Sun  I Prigione  H Xie  S Ferrini 《Tumori》1992,78(2):79-86
In an attempt to construct bispecific monoclonal antibodies (bimAbs) able to target cytotoxic T lymphocytes against human hepatoma cells, an HGPRT-deficient mutant of the Hepama-6 hybridoma, which produces an antihuman-hepatoma mAb, was directly fused with splenocytes from Balb/C mice immunized by a polyclonal cytotoxic T-cell line. Hybrid hybridomas were selected in HAT medium, and their supernatants were directly screened for the ability to induce IL-2-cultured cytotoxic T lymphocytes to kill hepatoma cells in a 51Cr-release assay. The selected hybrid hybridoma, termed DQ-33, secretes a bimAb, which reacts with a CD3-associated determinant. When resting peripheral-blood lymphocytes were used as effector cells, virtually no cytolytic activity could be induced by DQ-33, whereas phytohemagglutinin-activated lymphocytes that had been expanded in vitro in IL-2-containing medium could be efficiently targeted against hepatoma cells. Targeting by DQ-33 bimAb was analyzed on different subsets of IL-2-cultured lymphocytes. It was evident that CD+4-8+ TCR alpha/beta+ and CD3+4-8-TCR gamma/delta+ lymphocytes were efficiently induced by bimAb to lyse human hepatoma cells, whereas no induction of cytolysis could be observed when CD3 + 4 + 8-TCR alpha/beta+ cells were used as effectors. DQ-33 bimAb was also able to induce lymphokine secretion (IL-2, GM-CSF and TNF-alpha) by all the different subsets of lymphocytes analyzed in the presence of target cells expressing the relevant antigen, independent of the expression of cytolytic activity.  相似文献   
17.
丁螺环酮和阿普唑仑治疗广泛性焦虑研究   总被引:3,自引:0,他引:3  
目的:比较国产丁螺环酮和阿普唑仑治疗广泛性焦虑的疗效和不良反应。方法:对78例广泛性焦虑按照就医顺序分为两组,分别服用丁螺环酮(38例)和阿普唑仑(40例)。疗程6周。于治疗前及治疗第1、2、4、6周末进行汉密尔顿焦虑量表(HAMA)及副反应量表(TESS)评定疗效和不良反应。结果:丁螺环酮和阿普唑仑的疗效相仿,丁螺环酮的不良反应少且轻微,无过度镇静和肌肉松弛作用,不产生药物依赖。结论:丁螺环酮是治疗广泛性焦虑较为理想的药物。  相似文献   
18.
OBJECTIVE: To study the expression of S100 in oral submucose fibrosis(OSF). METHODS: Immunohistochemistry assay was performed on 10 cases of OSF, 10 cases of oral epithelial dysplasia (OED) and 8 cases of normal oral epithelium using monoclonal antibody against S100 protein. RESULTS: S100 did not express in the normal oral muscosal epithelium. The S100 positive nuclear staining was found in 50% of the OSF and OED cases, which was significantly higher than that in the normal oral epithelium (P < 0.05). But the positive staining in the OSF and OED cases had no difference (P > 0.05). CONCLUSION: S100 expression is closely related to the development of OSF and OED. The positive staining expression in the OSF and OED cases is the same.  相似文献   
19.
Inactivated whole avian influenza virus (AIV) vaccine provides protection against homologous haemagglutinin (HA) subtype virus, but poor protection against a heterologous HA virus. Moreover, it induces chickens to produce antibodies to cross-reactive antigens, especially nucleoprotein, which is limits AIV serological surveillance. In this study, a recombinant fowlpox virus co-expressing HA (H5 subtype) and NA (N1 subtype) genes of AIV was evaluated for its ability to protect chickens against intramuscular challenge with a lethal dose of highly pathogenic (HP) AIV. Susceptible chickens were also vaccinated by wing-web puncture with the parent fowlpox vaccine virus. Following challenge 4 weeks later with HPAIV, all chickens vaccinated with recombinant virus were protected, while the chickens vaccinated with either the unaltered parent fowlpox vaccine virus or unvaccinated controls experienced 100% mortality following challenge. This protection was accompanied by the high levels of specific antibody to the respective components of the recombinant vaccine. The above results showed that rFPV-HA-NA could be a potential vaccine to replace current inactivated vaccines for preventing AI.  相似文献   
20.
作者通过内窥镜对新疆奎屯地区氟中毒患者35名,氟砷中毒患者32名,对照组25名的胃粘膜进行观察,旨在了解氟元素和砷元素对胃粘膜的影响,在3个组中慢性胃炎的炎症程度与炎症活动性有显著性差异。2个中毒组间无显著性差异。结果表明在高氟区和高氟砷区患者的胃粘膜层病理改变主要是任性氟中毒引起,单纯性砷中毒并无协同作用。  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号